Active control of EIT-like response in a symmetry-broken metasurface with orthogonal electric dipolar resonators

The active control of electromagnetic response in metamaterial and mutual coupling between resonant building blocks is of fundamental importance in realizing high-quality metamaterials. In this work, we propose and experimentally demonstrate the tunabilities of symmetry-broken metasurfaces made of orthogonal electric dipolar resonators. The metasurface with vertical and horizontal wires is integrated with a PIN diode for active control.It is found that the electromagnetically induced transparency(EIT)-like spectrum appears due to the destructive or constructive interferences between the two electric dipolar modes when the structural symmetry broken is introduced to the metasurface. Different from previous works on the EIT-like effect, there is only electric dipole response in our metasuface. The microscopic response of the metasurface is numerically calculated to illustrate the mode coupling between the orthogonal electric dipolar resonators. By applying temporal coupled-mode theory,the interaction between the electromagnetic wave and the symmetry-broken metasurface is described, and the characteristic parameters of the resonator system, which determine the electromagnetic response of the metasurface, are acquired.

太赫兹多波段类电磁诱导透明超材料的研究

本文设计了一种多金属横条超材料结构,在0.5~1.2 THz之间产生多波段类电磁诱导透明(EIT-like)效应,改变上层金属条之间的间距以及电磁波的入射角度,发现所设计器件具有角度不敏感的特性。将上层金属横条都替换成石墨烯材料后,通过改变加载在石墨烯上的电压,可以调节EIT窗口,在慢光器件方面有潜在应用。

Coherent effect of triple-resonant optical parametric amplification inside a cavity with injection of a squeezed vacuum field

In theory, we study the quantum tluctuatlons ot tlae suDllarmonlc renecteu nela Irom a ulplc-rc^ulltUtt IdU^ClIClatC optical parametric amplifier （OPA） inside an optical cavity. We discuss two cases, where the linewidth of the harmonic field is either much narrower or broader than the subharmonic field. Since an electromagnetically-induced-transparency （EIT）-like effect can be simulated in a triple-resonant OPA, the output spectra from a triple-resonant OPA with a squeezed vacuum input may simulate the phenomenon of the response of an EIT medium for squeezed states. This scheme can be implemented with present experimental setups.

一种基于光子晶体的类EIT全光开关设计与分析

电磁诱导透明(Electromagnetically Induced Transparency,EIT)是一种由原子光激发介质通道之间的量子相干效应。该效应导致光在原子共振吸收频率处的吸收减小甚至于变成完全透明。因此,利用光学类EIT效应可以制作光通信系统中光开关器件。通过设计光子晶体结构,运用三维时域有限差分方法(3D-FDTD)进行仿真,结果显示在1 564 nm处能达到光开关的效果,可以将其运用到光通信领域之中,并发挥有效作用。

基于石墨烯杂化的类EIT太赫兹超表面仿真研究

太赫兹技术近年来受到各国研究者的重视,特别是针对太赫兹波的高效动态调制器件。提出了一种结合单层石墨烯与双金属环形类EIT结构的杂化太赫兹超表面调制器,该器件能够对类EIT效应实现调制且该器件具备偏振不敏感的优势。对该调制器件的电磁特性与调制能力进行了仿真分析,结果表明,双明模类EIT结构在0.565 THz处形成EIT峰,透射率达0.66。在石墨烯的调制作用下,杂化超表面EIT峰透射率的调制深度达44.9%,群延迟调制深度达22.8%。仿真结果验证了该杂化超表面对类EIT效应调制的有效性。该杂化超表面调制器在太赫兹通信、慢光调制等领域具有应用前景。